The present invention relates to improvement in or relating to a distributed feedback semiconductor laser.
A semiconductor laser, developed as a light source for optical fiber communications, which forms the basis of optical communication systems, has hitherto undergone various improvements for use as a light source of longterm stability and high performance, and in paticular, a distributed feedback semiconductor laser (hereinafter referred to simply as a DFB laser), which is capable of operating at a single wavelength, has been highlighted in recent years.
The DFB laser has an excellent effect in its wide application used as a light source for optical communications; at present, however, there has not been developed a DFB laser which is stable enough to be employed as a light source for high reliability optical communications.